After using GPS, I've found that radar took a lot of interpretation. You definitely want to practice using Radar on clear days, comparing your image to what you see out in front of you. I'm still not comfortable with looking at images of lumpy cotton candy (land masses), vague smears, (moving boats) and small rectangles.(ships)
I was struggling, so I bought several books on the matter. The one book that made the most sense started off saying " You want to use radar when you can't see out the window. You usually set the radar for 3 miles and use it for collision avoidance" Even so, I switched on the radar and noticed that I couldn't see a nearby sailboat. This is when I realize that I need to work on learning this new instrument. I'm getting better at setting the range, power and clutter controls.
I think the better radars will have sunlight viewable screens and the higher powered radoms. My friends have the big open array Furuno units and they can see the gulls diving on the bait. I've never seen that with my smaller Furuno 1723C.
I remember going with a group of crazed Albacore fishermen out of Santa Cruz. The skipper was going like heck, looking out the cabin window into the gray mist. On the way out, he was was jerking the boat to the starboard and port, dodging crab pot floats. Next to him, his buddy had his face pressed into the radar screen. He was calling out the locations of ships from time to time. Even so, at one point, we heard the deep, teeth vibrating blast of a ship's horn nearby. It was quite an experience.
From this, I learned that the skipper usually keeps an eye out in front of the boat and a second person ran the radar.